Various networks such as the Internet, a local area network (LAN), a wide area network (WAN), a mobile telephone network are being utilized for data communications. In a data communication network, a band control is often performed in order to avoid a situation where excessive traffic occurs on finite number of communication resources to cause a communication failure. In the band control, band may be limited for each communication entity from a viewpoint of ensuring impartiality between communication entities such as a user, an information processing apparatus and an application software.
For example, a band control apparatus has been proposed in which a band used by one or two or more Transmission Control Protocol (TCP) sessions and established by the user are summed up for each user, and the band is limited for the user whose total used band exceeds a threshold value. The band control apparatus decreases the TCP window size of a user to be subjected to the band limitation or delays the returning of ACK packet from TCP to implement the band limitation for each user.
In the meantime, a call connection system has been proposed in which a maximum band available in a communication terminal is measured, and, for example, an encoding speed, a packet length, a packet transmission interval, a packet priority and a codec class are dynamically changed according to whether the maximum band is the threshold value or more. The call connection system calculates the maximum band in the communication terminal based on a round-trip delay time of a packet or a packet loss ratio. Further, a data multiplexing method has been proposed in which data supplied from a plurality of sources are multiplexed for transferring. The data multiplexing method appends a session identifier and a packet serial number to data as header information upon multiplexing data.
International Publication No. WO 2005/006673, Japanese Patent Application Laid-Open No. 2007-36960 and Japanese Patent Application Laid-Open No. 2007-235356 have been known as prior art.